Electric heating unit



April 28, 1925.

J. G. WALLMANN ELECTRIC HEATING UNIT Filed April 10, 1922 Patented Apr. 28, 1925.

UNITED STATES PATENT OFFICE.

ELECTRIC HEATING UNIT.

Application filed April 10, 1922. Serial No. 550,993.

To all whom it may concern:

Be it known that I, JOIIANN G. VALL- MANN, a citizen of the United States, residing at Oakland. in the county-of Alameda and State of California, have invented certain new and useful Improvements in Electric Heating Units, of which the following is a specification.

My invention is an improved electric heating element;particularly suitable for bake ovens, driers, and other heating devices, constructed with novel controlling means whereby the use of portable cord plugs which get out of order very easily, areeliminated.

Referring to the annexed drawing in which my invention is illustrated and which forms a part of this specification:

Figure 1 is a side view 'of my electric. heating element in circuit closing position mounted in the lower part of an oven which is shown in vertical section.

Figure 2 is a plan view of my heating element.

Figure 3 is a fragmentary side view partly in section of my electric heating element in open circuit position.

Figure 4 is a detail view in section along line 4-4 of Fig. 2 showing the insulating saddles and the mounts therefor.

In the drawing 1 indicates a drawer in the form of a rectangular frame which slides in the lower part of a heating device 2 such as a bake oven, drier and the like through an opening 3 in said heating device. Rods 4 and 5 extend transversely of the frame 1 and are secured at their ends in the side walls of the frame the rod 4 being located toward the outer end of the frame and the rod 5 being located near the inner end of the frame. On the outer end wall of the frame 1 is secured a plate 6 of larger area than the said outer end wall which plate engages the outside of the wall of the heating device 2 and limits the inward movement of the drawer 1 in its circuit closing and heating position as shown in Figure 1. Angle iron 7 is secured to one side of the drawer 1 which engages the wall of the heating device 2 and limits the outward movement of the drawer 1 which is a. short movement. A wall of insulation 8 extends transversely of the drawer 1 between the forward end thereof and the rod 4. A brass expansion bracket 9 extends transversely of the frame 1 from one side wall thereof and-has an eye 10 at one end adjacent said side wall through which extends the rod 4. Nuts 11-11 screw on said rodagainst the inside of the side walls of the frame 1 to hold the rod in the frame. rod 4 against the sides respectively of the veye 10 and hold the bracket 9 rigidly on said Tuts 1S18 screw on the rod 5 against the inside of the side walls of the frame 1 and hold the rod in place inthe frame. A brass expansion bracket 19 extends transversely of the frame 1 from one side wall thereof and has an eye 20 at its end adjacent said wall through which extends the rod 5. Nuts 21 and 22 screw on said rod against the re-- spective sides of said eye whereby the bracket is held rigidly on said rod. A brass bracket 23 extends transversely of the drawer 1 from the other side thereof and has an eye 24 adjacent said side through which loosely extends the rod 5 whereby said bracket is'loosely mounted to slide on said rod. An iron tie plate 25 is interposed between the brackets 19 and 23 and said brackets and tie plate are all secured together by rivets 26. An iron bar 27 is secured at its ends to the outer end of the brackets 9 and 19 and an asbestos composition insulating saddle 28 fits over the outer edge of the bar 2?, said saddle having a plurality of longitudinally spaced notches 29 in its outer edge. An iron bar 30 is secured at its ends to the outer ends of the brackets 14 and 23 Nuts 12 and 13 also screw on the and a fibre insulating saddle 31 fits over the outer edge of the bar 30, said saddle having a plurality of longitudinally spaced notches 32 in its outer edge. A fine coil of wire 33 is coiled around the saddles 28 and 31 in the notches 29 and 32 and secured to screw terminals 34 and 35 at opposite ends of the saddle 28. A wire 36 is connected at one end to terminal 34 and at its other end to a terminal 37 on the wall 8. A wire 38 is connected at one end to terminal 35 and at its other end to a terminal 39 on the wall 8. A hollow handle 40 is secured at its upper end to the plate 6 in communication with apertures Wall'of'ithe' drawer 1.

411 and-4i2 in. said plate and My heating element is contr olled by an electric switch 45' which comprises apair of sockets 46 and 4t? and a pair of p lhgs and 49, said sockets being mounted na sw tch Wire box 50 secured to the under SlClQ ot the heating device 2 the tront thereot and said plugs being mounted onthe lower end; of said handle 40. throughthe handle 40- and .is connected at one end to terminal 39 and at itsothenend to plug 458-.

handle $0 and is connected atone end to terminal 3-? and at. its other; end to pliig49;

wires 53 and5 are connected respectively to sockets46and 47 in box :50 and extend through said box and.- are connecteddo a source of electric power (notshown).

To close the circuit incluiding my heating I element the drawer l'jis pushed all thewvay into the heating device 2; until the'plate 6 "iengages the Wall OfSBjid device in which position the plugs-egand-e9are introduced i11- to the sockets L6;and 4T respectively;closing' the, switch 45 1 Current passesirom thesw tch thcough wlre 51, termini-211619, Wire 38,

terminal 35,,ooil-33, terminal 34 wire 36,

-- 9. 14-, 19- and '23 be-ing greaterthan that 0''? terminal 37, and avire 52 back to the switch,

7 the currentheatingthe coil which generates heatjinthe heating device 2. "The co-; eliioient of expans on of the brass brackets the coil the bar- 30 and saddle 31 are moved away from the bar 2? andsad-dle'28 in the outer end 7 A- wire 5.1 extends A Wire-52 extends through the to such an exte nt as to takeup the slack in saidtoil and maintain said coil tantso that the individual coils thereof cannot come together and short circuit my heating element. Theheating-circuit isbroken by' pulling oiit the'dran'er 1 and disengaging the plugs 48 and d9 from the sockets 46 anddl, in

avh-ich position the hea-t in the heating device '2 escapes through the forward part of the drawer 1 and through the opening -Havmg described lny rinvent on, I clan-n: '1. In a heating element relatively movable insulating saddles su orts'therctor a coil 7 Wound around said saddles and'ineans com; prising a member adaptedto expandi-inder heat tog produce relative movement ot said saddles, one vend ot said member being fixed to a support and the other end ot said meniher being'slidabl-y Inountedonsaid support;

In a heating element, a drawer a pair of rods entending transversely of said drawer; brass brackets fixed on said rods re spectively, brass braclgetsslidahle on said rods respectively, an ironitie plate betweeneach painof fined and slidable-brackets to which; plate 1 brackets aresecured, a bar Secured at i In testimony whereof I affix invsignature. I w

' 7 JOHANNG. WA LrnnW. 

